NAVIGATION (NAV ARM
and
NAV
CPLD)
Mode
The NAV mode provides visual bank
commands on the Flight Command Indicator
and deviation guidance on the PNI
to
inter-
cept and track a VOR course or an RNAV
course.
Operation of the NAV mode requires the
pilot
to:
1.
Tune the frequency of the selected VOR
(or VORTAC) station. For RNAV operation,
set in waypoint distance and bearing from
the VORTAC station.
2.
Set the PNI course pointer on the de-
sired course.
3.
Establish angle of intercept by setting
heading "bug" and activate "HDG" mode.
4.
Depress the NAV button on the Mode
Controller.
When the "NAV" button on the Mode
Controller is depressed, "NAVIARM" will be
lighted on the Annunciator Panel and the
automatic capture circuit is armed. Heading
select, if operating, is retained until capture
occurs.
The VOR or RNAV "course-capture''
point is variable
to
prevent overshoot and
depends on angle of intercept and the rate
the course deviation is changing. Upon cap-
ture, a bank command will be displayed on
the FCI; the HDG, if on, will be cancelled and
"NAVICPLD" will be lighted on the Annun-
ciator Panel.
The pilot can manually bank the aircraft
to
satisfy the command display which will call
for a rollout
to
level flight when on course
centerlhne
to
track the course. Crosswind
compensation is provided in the "track
state.
If
the NAV mode is selected with the
aircraft level within
k4'
of bank and within
three dots of course deviation, NAVIARM will
be bypassed and NAVICPLD will engage
directly.
If the Autopilot
is
engaged, the aircraft
will bank
to
satisfy the command display and
rollout on course automatically.
Upon station (or waypoint) passage, an
outbound course other than the inbound re-
ciprocal can be selected by resetting the
NAV course arrow on the PNI. This will cause
an immediate V-bar deflection on the FCI di-
recting a turn
to
the,new course.
The NAV mode is cancelled by depress-
ing the NAV button, or selecting HDG (when
in NAV coupled) or APPR modes, or pushing
FD
to
"OFF'.
CAUTION:
The NAV mode of operation will
continue
to
provide airplane control without a
valid VOR/LOC signal (NAV flag in view).
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